xfs: turn io_append_trans into an io_private void pointer

In preparation for moving the ioend structure to common code we need
to get rid of the xfs-specific xfs_trans type.  Just make it a file
system private void pointer instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_aops.c

@@ -153,7 +153,7 @@ xfs_setfilesize_trans_alloc(
 	if (error)
 		return error;
 
-	ioend->io_append_trans = tp;
+	ioend->io_private = tp;
 
 	/*
 	 * We may pass freeze protection with a transaction.  So tell lockdep
@@ -220,7 +220,7 @@ xfs_setfilesize_ioend(
 	int			error)
 {
 	struct xfs_inode	*ip = XFS_I(ioend->io_inode);
-	struct xfs_trans	*tp = ioend->io_append_trans;
+	struct xfs_trans	*tp = ioend->io_private;
 
 	/*
 	 * The transaction may have been allocated in the I/O submission thread,
@@ -285,10 +285,10 @@ xfs_end_ioend(
 	else if (ioend->io_type == IOMAP_UNWRITTEN)
 		error = xfs_iomap_write_unwritten(ip, offset, size, false);
 	else
-		ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_append_trans);
+		ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_private);
 
 done:
-	if (ioend->io_append_trans)
+	if (ioend->io_private)
 		error = xfs_setfilesize_ioend(ioend, error);
 	xfs_destroy_ioends(ioend, error);
 	memalloc_nofs_restore(nofs_flag);
@@ -321,13 +321,13 @@ xfs_ioend_can_merge(
  * as it is guaranteed to be clean.
  */
 static void
-xfs_ioend_merge_append_transactions(
+xfs_ioend_merge_private(
 	struct xfs_ioend	*ioend,
 	struct xfs_ioend	*next)
 {
-	if (!ioend->io_append_trans) {
-		ioend->io_append_trans = next->io_append_trans;
-		next->io_append_trans = NULL;
+	if (!ioend->io_private) {
+		ioend->io_private = next->io_private;
+		next->io_private = NULL;
 	} else {
 		xfs_setfilesize_ioend(next, -ECANCELED);
 	}
@@ -349,8 +349,8 @@ xfs_ioend_try_merge(
 			break;
 		list_move_tail(&next->io_list, &ioend->io_list);
 		ioend->io_size += next->io_size;
-		if (next->io_append_trans)
-			xfs_ioend_merge_append_transactions(ioend, next);
+		if (next->io_private)
+			xfs_ioend_merge_private(ioend, next);
 	}
 }
 
@@ -415,7 +415,7 @@ xfs_end_bio(
 
 	if (ioend->io_fork == XFS_COW_FORK ||
 	    ioend->io_type == IOMAP_UNWRITTEN ||
-	    ioend->io_append_trans != NULL) {
+	    ioend->io_private) {
 		spin_lock_irqsave(&ip->i_ioend_lock, flags);
 		if (list_empty(&ip->i_ioend_list))
 			WARN_ON_ONCE(!queue_work(mp->m_unwritten_workqueue,
@@ -680,7 +680,7 @@ xfs_submit_ioend(
 	    (ioend->io_fork == XFS_COW_FORK ||
 	     ioend->io_type != IOMAP_UNWRITTEN) &&
 	    xfs_ioend_is_append(ioend) &&
-	    !ioend->io_append_trans)
+	    !ioend->io_private)
 		status = xfs_setfilesize_trans_alloc(ioend);
 
 	memalloc_nofs_restore(nofs_flag);
@@ -729,7 +729,7 @@ xfs_alloc_ioend(
 	ioend->io_inode = inode;
 	ioend->io_size = 0;
 	ioend->io_offset = offset;
-	ioend->io_append_trans = NULL;
+	ioend->io_private = NULL;
 	ioend->io_bio = bio;
 	return ioend;
 }

fs/xfs/xfs_aops.h

@@ -18,7 +18,7 @@ struct xfs_ioend {
 	struct inode		*io_inode;	/* file being written to */
 	size_t			io_size;	/* size of the extent */
 	xfs_off_t		io_offset;	/* offset in the file */
-	struct xfs_trans	*io_append_trans;/* xact. for size update */
+	void			*io_private;	/* file system private data */
 	struct bio		*io_bio;	/* bio being built */
 	struct bio		io_inline_bio;	/* MUST BE LAST! */
 };